Alternating-current synchronous motor.



R. W. SWIFT.

ALTERNATING CURRENT SYNCHRONOUS MOTOR.

APPLiCATION FILED 020.4.1914.

Patented May 15, 1917.

Wane/bows UNITED STATES PA T ornron ROBERT w. SWIFT, or wARREiLoHIo, AssIGiqoR To THE PEERLESS ELECTRIC. COMPANY, 01 WARREN, 01110, A CORPORATION OF OHIO.

to provide an improved induction motor for single or polyphase circuits equipped with means for causing the rotor to operate in exact synchronism with the alternations of;

the current.v and to avoid lagging or slippage of the rotor relative to the pulsations of thecurrent.

I provide on the rotor or secondary member two short circuited' conducting paths for the induced current. These may be of the same or different conductivities. One is symmetrical with the polar field and the other unsymmetrical with relation to the polar field.

In the accompanying drawing, Figure 1 is a section-of an alternating current motor equipped with my improvement. Fig. 2' is a section on line 22, Fig. 1. Fig. 3 is a view similar to Fig. l but showing an alternative arrangement. Fig. 4 is a sec tion on line 44, Fig. 3/ V Referiingtothe drawings, 1 designates the stator or inducing member which may be either of solid ironor built up of soft iron disks and shown formed with slots wherein are inserted an even number 'of polar or field windings constituting a distributed Wound field circuit. v

In Figs'l and 2 I have shown the rotor or secondary member 2 provided at its'periphery with .four series of groups or sections composed-of current conducting members forming two electrical paths, one of which preferably has a greater conductivity than the other, although the conductivities may be thesame. The conductors formingone path, preferably the greater, are located symmetrically in relation to the polar fieldof the stator, while theconductors forming the other or lesser patli are of themselves unsymmetrical in relation to such field.v I have shown the conductorsof the unsymmetrical or lesser path; consisting of an odd ---Ihe advantages of my invention constitute ,a substantially integra closed circuits.

As shown in Figs. 2 and 4 the described; arrangement may be reversed, that is to say, the. rotor-5 may contain thepolar field and ALTERNATING-CURBENT SYNGHRONOUS MOTOR.

Specification of Letters Patent. Patented 1\Ia,y 15,- 1917, Application ma December 4, 1914. Serial No. eat-5,448.

or uneven number of plugs 3, preferably of copper, extending through the rotorat its periphery. They are separated by the four relatively large copper bars 4' constituting the symmetrical or greater path. The

surface or periphery of the rotor is interrupted at the points of location of the bars 4 to provide seats or recesses for the. bars.

As a result of the described arrangement the number of plugs 3 is prime to the stator pole number and provides a conducting path unsymmetrical relative to the stator poles.

The four bars 4, however, are equally spaced about the periphery of the rotor and are of correspondingsizes and therefore in exact diametrical arrangement.

. '7 In so arranging the bars it is immaterial whetherthey cut cross sectional area greater than the" Gomblned cross sectional area of the copperplugs. Hence, after the plugs have effected,

the starting, the bars, by their greater conductivity, produce a current greater than the plugs, thus overcoming the tendency of the rotor to lag relative to the pulsations of the current.v

The copper bars are united electrically to 1 the copper plugs, thereby constituting an in;

tegral solid structure with two electrical paths. The bars may be soldered or welded at their ends to the plugs. The rotor may be composed of an iron core with the plugs and bars tightly'inserted and so arranged and unitedby soldering or 'weldin solid structure and form thedesired' number of as to individually and collectively con-.

al to the poles of the stator 6 may be equipped with the" groups or sections of plugs and intermedlate will be readily appreciated by those skilled in the art, and it will be seen that by means thereof the synchronism of an alternating current motor is insured, and that the same results may be obtained by constructing either the rotor or the stator in accordance with my lnvention.

I claim as my invention:

. 1. In an induction motor, in combination, a stator and a rotor, one member having a polar field and the other an electrical path which is symmetrical with said field and E piath which is unsymmetrical with said 2. In an induction motor, in combination, a stator and a'rotor, one member having means for producing a given number of poles therein, and the other member having a number of conductors prime to said pole number, connected to provide a conducting path unsymmetrical to said poles, and also provided with an electrically conducting path symmetric thereto.

3. In an induction motor, in combination,

a. stator and a rotor, one'member having an even number of polar windings and the other an odd or uneven number of plugs, a plurality of bars dividing said plugs, said plugs and bars forming two electrical paths one of which is symmetrical with said windings and the other unsymmetrical with said windings.

4. In an induction motor, in combination, a stator and a rotor, one member having an even number of polar windings and the other an odd or uneven number of plugs, a plurality of bars dividing said plugs, said plugs and bars forming two electrical paths, the conductivity of said bars being greater than that of said plugs.

' 5. In an induction motor, in combination, a stator having an even number of polar windings and a rotor having an odd'or uneven number of-plugs unsymmetrical with relation to said polar windings, and a plurality of bars equally spaced and separating said plugs into series, said bars being in symmetrical relation to said windings.

6. In an induction motor, in combination,

a stator having polar windings and a rotor having plugs at its periphery unsymmetrical with relation to said windings, bars separating 4 said plugs and symmetrical with said windings, said bars dividing said plugs into grou s or sections of which the respective bars f orm parts, said groups or sections being symmetrical with said windings.

In testimony whereof, I have signed this specification in the presence of two subscribing witnesses.

ROBERT IV. SWIFT.

Witnesses:

M. E. RIDER, V. C. "WARD. 

